Alkaline Leaching of a Uranium Metal from the Ore Using EDTA

This paper deals with the leaching studies on a calcite ore containing radioactive element (U) in low concentrations. Uranium distributed in the ore in very wide range but it is very low concentrations. Recovery of Uranium in economical way is the primary requirement. Ore itself contains more amount of carbonate content so we have used alkaline leaching which is very economical. Ore samples of four different grades from the same deposit have been investigated for the leachability of radioactive metal. The radioactive metal concentrations of the ore samples studied are: Sample A, B, C and D assaying 179 ppm,250 ppm, 392 ppm and 414 ppm respectively. The ore of particular grade was ground to 60% passing 75 μ sizes. Alkaline leaching of the ground ore was carried out in two stages. The first stage was carried out with sodium carbonate and sodium bicarbonate along with aeration at atmospheric pressure and 70oC for 6 hr. The residual cake after filtration was subjected to second stage of leaching using EDTA solution for 3 hr., 50% solids (by wt.), atmospheric pressure and 70oCin an attempt to increase the yield of the metal. The two stage leaching was carried out for four ore samples of different grades. The ore gangue constitutes a reactive component, pyrite, which also undergoes leaching. Hence, its concentration also monitored along with that of desired metal. The two stage leaching process tested in this study has yielded maximum of 58% recovery of metal into the leach liquors of both stages.